This invention relates in general to vacuum producing apparatus and deals more particularly with improvements in central vacuum cleaning system.
Central vacuum systems of the type with which the present invention is concerned are typically found in office buildings, hospitals, hotels, schools and industrial plants, for example. The basic components of such central vacuum system installations essentially comprise a vacuum producer and a separator or separators for collecting dust, dirt and liquid and solid waste materials and for reclaiming valuable scrap materials produced in an industrial process, if desired. The components further include a piping system which has inlet valves or ports in areas of a building to be cleaned and a network of tubular conduit for conveying vacuumed material to a central collection point for removal or disposal.
In a commercial or industrial installation, the vacuum producer and separator or separators may be installed at a remote location in a building, such as a basement or equipment room. This arrangement isolates the collected materials, including contaminants, from areas of the building that have been cleaned, thereby helping to maintain healthful environmental conditions in the building.
Inlet valves positioned at desired locations throughout a building are connected to the tubular conduit network which carries the vacuumed material to the central collection point. Portable hoses with attachments for vacuum pick-up and which can be inserted into and coupled to the inlet valves are employed for local area vacuum cleaning. A wide variety of vacuum pick-up tools are presently available to satisfy the diverse cleaning and material pick-up jobs encountered in normal maintenance of a commercial building or industrial plant, for example.
In a system of the aforedescribed general type, in order to supply vacuum at peak demand, it may be necessary to operate the vacuum producer at about 60% of load capacity all times, so that required vacuum will always be substantially immediately available at every inlet valve or valve port throughout a building, even though most of the valve ports are not in use much of the time. Such systems are often provided with a simple on/off switching device and maintained in operation at all times during hours of normal usage. Other systems, subject to less frequent usage, may include remote starting and stopping devices positioned at numerous locations throughout a building in which the system is installed. However, the provision of such multiple control devices requires a substantial amount of additional wiring throughout the building and adds substantially to system installation cost.
Accordingly, it is the general aim of the present invention to provide an improved demand responsive central vacuum system which conserves power during normal use and which affords opportunity for reduced installation cost.